<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02变量与常量</title>
</head>
<body>
<script>
  var a = 10;
  var b = 3.1415926;
  var c = "玥玥";
  var d = "nb";
  var e = true;
  console.log(a,b,c,d,e);
  console.log(typeof a,typeof b,typeof c,typeof d,typeof e);
  a = false;
  console.log(a,typeof a);
  var a = "我又来啦！";
  console.log(a,typeof a);
  let x = 1;
  console.log(x,typeof x);
  x = "啦啦啦";
  console.log(x,typeof x);
  // let 声明的变量可以更改数据类型，但是不能重复声明
  const y = 2;
  console.log(y,typeof y);
//  const 表示常量，常量不能重复声明，常量的值一旦被设定，就不能被修改
</script>
</body>
</html>